The studio that made mobile smash Fruit Ninja's letting you have their latest blockbuster title for free today. Halfbrick's slashed the price of Jetpack Joyride from 0.99 to 0.00 today on Apple's App Store. The freewheeling sidescroller's also added new unlockable items with its 1.2.5 update, including a Deck The Halls Jetpack shaped like a Christmas tree.